Stellar Twister

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October 11, 2012

The last gasps of a dying star form a spiral structure around the star R Leporis in this image from ALMA, a new radio telescope in Chile. The image was created by taking a "slice" of data gathered by ALMA's sensitive antennas. R Leporis is a red giant -- an aging star that has puffed up to many times its original size. Waves of instability in its core cause it to eject thick shells of gas and dust, one of which forms the outer ring in this image. Between shells, it emits a thick stream of particles known as a stellar wind. An unseen companion star may be stirring up this gas, forming the spiral structure seen in the image. The entire complex of gas and dust around the star is known as a planetary nebula. [ALMA (ESO/NAOJ/NRAO)]